Fastener-driving tool having a superconductor power source

ABSTRACT

The present disclosure provides various embodiments of a fastener-driving tool that includes a battery-charged supercapacitor as a power source. The fastener-driving tool includes first and second spaced-apart, conductive rails and a partially conductive piston slidably mounted on the rails. The rails and the piston are electrically connected to one another. The supercapacitor is electrically connected to the first rail. When the supercapacitor discharges electrical current, the electrical current flows from the supercapacitor, into the first rail, through the piston into the second rail, and from the second rail. The electrical current induces magnetic fields in the rails and the piston, and the combination of the electrical current and the magnetic fields induce a Lorentz force that acts on the piston to move the piston toward a nosepiece to drive a fastener.

PRIORITY

This application is a continuation of, and claims priority to and thebenefit of, U.S. patent application Ser. No. 16/851,816, filed on Apr.17, 2020, which is a continuation of, and claims priority to and thebenefit of U.S. patent application Ser. No. 15/801,521, filed on Nov. 2,2017, now issued as U.S. Pat. No. 10,632,602 on Apr. 28, 2020, whichclaims priority to and the benefit of U.S. Provisional PatentApplication Ser. No. 62/425,825, filed Nov. 23, 2016, the entirecontents of each of which are incorporated herein by reference.

BACKGROUND

Powered fastener-driving tools are well known and widely used throughoutthe world. Generally, powered fastener-driving tools employ one of avariety of power sources to drive a fastener into a workpiece. Morespecifically, a powered fastener-driving tool uses a power source todrive a piston carrying a driver blade through a cylinder from apre-firing position to a firing position. As the piston moves to thefiring position, the driver blade enters a nosepiece, which guides thedriver blade into contact with a fastener housed in the nosepiece.Continued movement of the driver blade through the cylinder forces thefastener from the nosepiece and into the workpiece.

Three main types of fastener-driving tools exist: (1) pneumaticfastener-driving tools that use compressed air as a power source; (2)combustion fastener-driving tools that use a combustion engine as apower source; and (3) electric fastener-driving tools that use anelectric motor as a power source. Each type of fastener-driving tool hascertain advantages and certain disadvantages.

Pneumatic fastener-driving tools rely on a compressed air source, whichadds to the cost of the tool since an air compressor must be purchased(or rented) and maintained. Pneumatic fastener-driving tools alsorequire a compressed air hose to be attached to the tool during use tosupply the compressed air. The user may spend time inspecting the hosefor cracks or other defects that would reduce how much compressed airreaches the tool (reducing performance), which slows the user down.Further, replacing broken hoses increases costs.

Combustion fastener-driving tools rely on fuel cells to function. Thefuel cells include liquid fuel that is meted out into a combustionchamber and ignited to drive the piston. The fuel cells must eventuallybe replaced, which increases the lifetime cost of ownership ofcombustion fastener-driving tools and requires users to spend timechecking the fuel supply.

Electric fastener-driving tools typically rely on large and heavyelectric motors to obtain sufficient fastener-driving power.

A continuing need exists to develop new and improved fastener-drivingtools that are lighter, less expensive, and easier to operate andmaintain than existing fastener-driving tools.

SUMMARY

The present disclosure provides various embodiments of afastener-driving tool that includes a battery-charged supercapacitor asa power source. The fastener-driving tool includes first and secondspaced-apart, conductive rails and a partially conductive pistonslidably mounted on the rails. The rails and the piston are electricallyconnected to one another. The supercapacitor is electrically connectedto the first rail. When the supercapacitor discharges electricalcurrent, the electrical current flows from the supercapacitor, into thefirst rail, through the piston into the second rail, and from the secondrail. The electrical current induces magnetic fields in the rails andthe piston, and the combination of the electrical current and themagnetic fields induce a Lorentz force that acts on the piston to movethe piston toward a nosepiece to drive a fastener.

Unlike pneumatic fastener-driving tools, compressed air doesn't powerthe fastener-driving tool of the present disclosure, which leads tolower costs and easier use. Unlike combustion fastener-driving tools,the fastener-driving tool of the present disclosure does not requirereplaceable fuel cells, which also leads to lower costs and easier use.Unlike electric fastener-driving tools, the fastener-driving tool of thepresent disclosure does not need a large and heavy electric motor togenerate sufficient fastener-driving power. Instead, thefastener-driving tool of the present disclosure uses relativelylightweight rails and superconductors to generate power for fastenerdriving, which leads to easier use.

Other objects, features, and advantages of the present disclosure willbe apparent from the detailed description and the drawings.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view of one example embodiment of thefastener-driving tool of the present disclosure.

FIGS. 2 to 8 are partial schematic views of the fastener-driving tool ofFIG. 1 during various stages of capacitor charging and fastener driving.

DETAILED DESCRIPTION

Referring now to the drawings, FIGS. 1 to 8 illustrate one exampleembodiment of a fastener-driving tool 10 of the present disclosure. Thisexample embodiment of the fastener-driving tool 10 drives nails and isreferred to below as a “rail nailer.” In other embodiments, thefastener-driving tool may drive any suitable types of fasteners otherthan nails (such as brads or staples). The example rail nailer 10includes: (1) a housing 12; (2) a power system 100 that powers variouscomponents of the rail nailer 10; (3) spaced apart, generally parallelfirst and second conductive rails 35 a and 35 b (also called “rails” forbrevity); (4) an at least partially conductive piston 50 (also calledthe “piston” for brevity); (5) a driver blade 55; (6) a trigger 26; (7)a trigger switch (not shown); (8) a nosepiece 28; (9) a fastenermagazine 30; (10) a workpiece contact element (WCE) 32; (11) a WCEswitch (not shown); (12) a linkage 34; (13) a WCE biasing member 38;(14) a piston movement and locking assembly including a pair of firstsprings 40 a and 40 b; and (15) a piston return assembly including apair of second springs 45 a and 45 b.

As best shown in FIGS. 2 to 8 , the first and second rails 35 a and 35 bare at least partially enclosed within and supported by the housing 12and oriented so their longitudinal axes are generally parallel to a mainaxis A of the rail nailer 10. The first and second rails 35 a and 35 bare made of a conductive material, such as copper or a copper alloy,coated with a conductive material that tolerates high temperatures andreduces friction between the rails 35 a and 35 b and the piston 50. Thisconductive material may include, for instance, vitreous carbon,graphite, graphene, metal carbides (e.g., zirconium carbide or titaniumcarbide), metal nitrides (e.g., titanium nitride or tantalum nitride),indium tin oxide, or any other suitable material. In certainembodiments, the first and second rails 35 a and 35 b are tubular inthat they each define a bore or partial bore generally aligned withtheir respective longitudinal axes. In certain embodiments, the bores orpartial bores of the first and second rails 35 a and 35 b are filledwith phase change material to dissipate heat, and specifically to absorbthe heat generated during fastener driving. The phase change materialcould include, for instance, Wood's metal, Rose's metal, or any othersuitable fusible metal alloy.

As best shown in FIGS. 2 to 8 , the piston 50 has a body that definestwo through holes sized to receive the first and second rails 35 a and35 b to enable the piston 50 to be slidably mounted to the first andsecond rails 35 a and 35 b. Once mounted to the first and second rails35 a and 35 b, the piston 50 is movable relative to the first and secondrails 35 a and 35 b between a pre-firing position (FIGS. 2, 3, and 8 )and a firing position (FIG. 6 ). Part of the portion of the body of thepiston 50 between the first and second rails 35 a and 35 b is made of asuitable conductive material, such as copper or a copper alloy. Otherportions of the body of the piston 50 may be made of any suitableconductive or non-conductive materials, such as molded fiberglass,plastic, or other metals. Similar to the rails 35 a and 35 b, the innersurfaces of the through holes are coated with a conductive material thattolerates high temperatures and reduces friction between the first andsecond rails 35 a and 35 b and the piston 50 (such as any of thematerials described above with respect to the conductive coating of thefirst and second rails 35 a and 35 b). In other embodiments, the pistonis not mounted directly to the rails, but is nevertheless electricallyconnected to and slidable relative to the rails.

The piston 50 and the first and second rails 35 a and 35 b, andparticularly the thickness of the piston and the cross-sectional areasof the first and second rails perpendicular to their longitudinal axes,are sized to ensure the contact area between the piston and the firstand second rails is large enough to conduct the requisite electricalcurrent and to dissipate the heat the electrical current generates. This(in part) prevents the high heat generated during fastener driving fromwelding the piston 50 to the first and second rails 35 a and 35 b.

As best shown in FIGS. 2 to 8 , the driver blade 55 extends from thepiston 50 in the direction of the nosepiece 28. A longitudinal axis ofthe driver blade 55 is generally aligned with the main axis A of therail nailer 10.

The piston movement and locking assembly is configured to hold thepiston 50 in the pre-firing position and to initiate piston movementupon closure of the discharge switch 125. As best shown in FIGS. 2 to 8, the piston movement and locking assembly includes the first springs 40a and 40 b respectively mounted on the first and second rails 35 a and35 b near their first ends. The piston movement and locking assemblyalso includes a locking device (not shown) that is configured to engagethe piston 50 and hold the piston 50 in the pre-firing position. Incertain embodiments, the locking device includes one or more mechanicallinkages operably connected to the WCE 32, the trigger 26, or both somovement of the WCE 32 from the WCE rest position to the WCE firingposition and/or movement of the trigger 26 from the trigger restposition to the trigger firing position causes the mechanical linkage tomove to release the piston 50. In other embodiments, the locking deviceincludes one or more electromechanical components controlled by acontroller that causes the locking device to release the piston 50 whencertain conditions are met (such as the conditions for fastener drivingdescribed below with respect to the rail nailer operating modes).

The piston return assembly is configured to return the piston to thepre-firing position after the driver blade 55 drives a fastener. In thisexample embodiment, the piston return assembly includes the secondsprings 45 a and 45 b respectively mounted on the first and second rails35 a and 35 b near their second ends opposing their first ends.

As best shown in FIG. 1 , the nosepiece 28 is connected to the housing12, and the fastener magazine 30 is attached to the nosepiece 28 suchthat the fastener magazine 30 can feed fasteners into the nosepiece 28.The nosepiece 28, the first and second rails 35 a and 35 b, the piston50, and the driver blade 55 are sized, shaped, and oriented relative toone another to enable the driver blade 55 to drive fasteners that thefastener magazine 30 feeds into the nosepiece 28 into a workpiece (notshown).

As best shown in FIG. 1 , the nosepiece 28 includes the WCE 32. The WCE32 is movable relative to the housing 12 between a WCE rest position inwhich the WCE 32 is a first distance from the housing 12 and a WCEfiring position in which the WCE 32 is a second, shorter distance fromthe housing 12. Movement of the WCE 32 from the WCE rest position to theWCE firing position causes the WCE to activate a WCE switch (not shown),such as via the linkage 34. The WCE biasing member 38, which is a springin this example embodiment, biases the WCE 32 to the WCE rest position.

As best shown in FIG. 1 , the trigger 26 is supported by the housing 12,and is movable (such as pivotable) between a trigger rest position and atrigger firing position. Movement of the trigger 26 from the triggerrest position to the trigger firing position causes the trigger 26 toactivate a trigger switch (not shown).

As best shown in FIGS. 2 to 8 , the power system 100 includes: (1) abattery 110; (2) a resistor 115; (3) a charge switch 120; (4) adischarge switch 125; (5) first and second capacitors 130 a and 130 b;(6) a battery management system (not shown); and (7) one or more diodes(not shown).

The resistor 115 is electrically connected to the battery 110 and to thecharge switch 120. The charge switch 120 is electrically connected tothe discharge switch 125 and to the first and second capacitors 130 aand 130 b. The first and second capacitors 130 a and 130 b areelectrically connected to the battery 110 and to the first rail 35 a.The discharge switch 125 is electrically connected to the second rail 35b. Since (as described above) the piston 50 is at least partiallyconductive, the piston 50 is electrically connected to the first andsecond rails 35 a. The battery management system is communicativelyconnected to the battery 110, the charge switch 120, and the first andsecond capacitors 130 a and 130 b.

The battery 110 is a rechargeable, lithium-ion battery (or otherrechargeable or non-rechargeable battery having a suitably high energydensity) operable to charge the first and second capacitors 130 a and130 b when the charge switch 120 is closed (described below). The railnailer 10 may include or be electrically connectable to any othersuitable power source to charge the first and second capacitors 130 aand 130 b other than or in addition to a battery. In variousembodiments, the battery 110 powers one or more other components of therail nailer 10, such as a controller, one or more lights, one or moredisplays, or one or more speakers.

The resistor 115 is any suitable resistor configured to slow the rate atwhich the battery 110 charges the first and second capacitors 130 a and130 b when the charge switch 120 is closed. This reduces the likelihoodof damaging the battery 110 by reducing rapid discharge of battery powerduring capacitor charging. In certain embodiments, the power systemdoesn't include a resistor.

The charge switch 120 is any suitable electrical or electromechanicalswitch configured to: (1) close to complete an electrical charge circuitamong the battery 110, the resistor 115, and the first and secondcapacitors 130 a and 130 b to enable electrical current to flow from thebattery 110, through the resistor 115, and to the first and secondcapacitors 130 a and 130 b to charge the first and second capacitors 130a and 130 b; and (2) open to break the charge circuit and prevent thebattery 110 from charging the first and second capacitors 130 a and 130b.

The first and second capacitors 130 a and 130 b include, for instance,any suitable high-power density electrochemical supercapacitors. Thearrangement of the supercapacitors in the rail nailer 10 (e.g., withinthe housing 12) depends on the supercapacitor size, weight, voltage, andcurrent. In certain embodiments, the first and second capacitors 130 aand 130 b have high energy and current densities that enable more than100 amps of electrical current to pass through the piston 150 when thetrigger switch 125 is closed. For example, Illinois Capacitor Inc.offers the superconductors listed in Table 1 below. The rail nailer mayinclude any suitable quantity of capacitors.

TABLE 1 Max Operating Dimension Cap Current Current Weight Volume D × L(F) VDC (A) (A) (g) (ml) (mm) 200 2.5 250 50 39.39 35.343 30 × 50  12002.5 1500 300 350 197.92 60 × 70  2000 2.5 2500 500 480 339.29 60 × 1203000 2.5 3000 750 623.8 452.39 60 × 160

The discharge switch 125 is any suitable electrical or electromechanicalswitch configured to open and close rapidly under the high currentgenerated by the first and second capacitors 130 a and 130 b. Thedischarge switch 125 may be, for instance, a solenoid direct-currentswitch, a thyristor, a silicon-controlled rectifier, a high-currentmechanical relay, a bipolar transistor, or a field-effect transistor.The discharge switch 125 is configured to: (1) close to complete adischarge electrical circuit among the first and second capacitors 130 aand 130 b, the first rail 35 a, the piston 50, and the second rail 35 ato enable electrical current to flow from the first and secondcapacitors 130 a and 130 b, through the first rail 35 a into the piston50, through the piston 50 and into the second rail 35 b; and (2) open tobreak the discharge circuit and prevent the first and second capacitors130 a and 130 b from discharging electrical current.

The diodes (not shown) prevent: (1) electrical current discharged fromthe first and second capacitors 130 a and 130 b from traveling to thebattery 110; and (2) electrical current discharged from the battery 110from reaching the discharge switch 125.

The battery management system (not shown) is operably connected to thecharge switch 120 and configured to automatically control whether thecharge switch 120 is open (to enable the battery 110 to charge the firstand second capacitors 130 a and 130 b) or closed (to prevent the battery110 from charging the first and second capacitors 130 a and 130 b). Morespecifically, the battery management system includes a controller andone or more monitoring devices (such as one or more sensors).

In certain embodiments, the controller includes a processing devicecommunicatively connected to and configured to execute instructionsstored in a memory device to control operation of the battery managementsystem. The processor may be, for instance, a general-purpose processor;a content-addressable memory; a digital-signal processor; anapplication-specific integrated circuit; a field-programmable gatearray; any suitable programmable logic device, discrete gate, ortransistor logic; discrete hardware components; or any combination ofthese. The memory device is configured to store, maintain, and providedata as needed to support the functionality of the battery managementsystem, such as program code or instructions executable by the processorto control the battery management system. The memory device may be anysuitable data storage device, such as one or more of: (1) volatilememory (e.g., RAM, which can include non-volatile RAM, magnetic RAM,ferroelectric RAM, and any other suitable forms); (2) non-volatilememory (e.g., disk memory, FLASH memory, EPROMs, EEPROMs,memristor-based non-volatile solid-state memory, etc.); (3) unalterablememory (e.g., EPROMs); and (4) read-only memory.

The monitoring devices are configured to monitor the charge levels ofthe first and second capacitors 130 a and 130 b. The controller isconfigured to maintain the charge switch 120 closed (to enable thebattery to charge the capacitors) so long as the charge level of atleast one of the first and second capacitors 130 a and 130 b is below anupper charge level threshold, such as the capacitor's maximum chargelevel or any other suitable charge level.

After the controller determines that the charge levels of both of thefirst and second capacitors 130 a and 130 b have reached the uppercharge level threshold, the controller is configured to automaticallyopen the charge switch 120 to stop the flow of electrical current fromthe battery 110 to the first and second capacitors 130 a and 130 b. Thecontroller continues to monitor the charge levels of both of the firstand second capacitors 130 a and 130 b, and is configured to close thecharge switch 120 responsive to the charge level of at least one of thefirst and second capacitors 130 a and 130 b falling below the uppercharge level threshold. In other embodiments, the controller isconfigured to close the charge switch 120 responsive to the charge levelof at least one of the first and second capacitors 130 a and 130 bfalling below a lower charge level threshold that is lower than theupper charge level threshold. In one example embodiment, the lowercharge level threshold reflects a charge level at which the capacitorsdo not have enough charge to enable normal fastener driving.

The battery management system is also configured to monitor the power orcharge remaining in the battery and to shut down the rail nailer whenthe battery power falls below a threshold (such as 25% charge remaining)to protect the battery from overworking itself and reducing itslifetime.

Generally, and as described in detail below, closing the dischargeswitch 125 completes the discharge circuit and causes the piston 50 tomove toward the nosepiece 28, which guides the driver blade 55 tocontact and drive a fastener housed in the nosepiece 28 from thenosepiece 28 into a workpiece.

The rail nailer 10 is operable in one of two modes to close thedischarge switch and initiate fastener driving: a sequential actuationmode and a contact actuation mode. In certain embodiments, the railnailer 10 includes a mechanical or electromechanical switch, button, orother device that enables the user to select whether the rail nailer 10operates in the sequential actuation mode or the contact actuation mode.In other embodiments, the rail nailer 10 is configured, such as throughone or more mechanical, electromechanical, or electrical systems, toautomatically switch between the sequential actuation mode and thecontact actuation mode responsive to certain conditions being met orcertain events occurring.

In the sequential actuation mode, the discharge switch closes responsiveto activation of the WCE switch followed by activation of the triggerswitch. For instance, to close the discharge switch 125 and drive afastener when the rail nailer 10 is in the sequential actuation mode, auser depresses the WCE 32 against a workpiece until it moves to the WCEfiring position, thereby activating the WCE switch, and then pulls thetrigger 26 to move the trigger to the trigger firing position, therebyactivating the trigger switch. Activation of the WCE switch alone,activation of the trigger switch alone, or activation of the triggerswitch immediately before activation of the WCE switch will not closethe discharge switch 125 when the rail nailer 10 is in the sequentialactuation mode. To drive another fastener, the user releases the trigger26 to enable it to return to the trigger rest position, removes the WCE32 from the workpiece to enable it to return to the WCE rest position,and repeats the above process.

In the contact actuation mode in which the trigger 26 remains in thetrigger firing position, the user first drives a fastener according tothe process described above for the sequential actuation mode.Thereafter, so long as the trigger 26 remains in the trigger firingposition, the discharge switch closes responsive to activation of theWCE switch. For instance, to close the discharge switch 125 and drive afastener when the rail nailer 10 is in the contact actuation mode, auser holds the trigger 26 in the trigger firing position and depressesthe WCE 32 against a workpiece until it moves to the WCE firingposition, thereby activating the WCE switch. The user then removes theWCE 32 from the workpiece to enable it to return to the WCE restposition, and repeats the above process.

FIGS. 2 to 8 show schematic views of the power system 100, the first andsecond rails 35 a and 35 b, the first springs 40 a and 40 b, the secondsprings 45 a and 45 b, the piston 50, and the driver blade 55 in variousstages of operation of the rail nailer 10 during capacitor charging andfastener driving.

FIG. 2 shows the rail nailer 10 while the charge switch 120 is closed tocomplete the charge circuit and the battery 110 is charging the firstand second capacitors 130 a and 130 b. The discharge switch 125 is open.

FIG. 3 shows the rail nailer 10 after the battery management system hasdetermined that the charge levels of the first and second capacitors 130a and 130 b have reached the upper charge level threshold and has openedthe charge switch 120. The discharge switch 125 is also open.

FIG. 4 shows the rail nailer 10 just after the discharge switch 125 hasclosed. In this example embodiment, closure of the discharge switchcauses the locking device of the piston movement and locking assembly tounlock and release the piston 50. This enables the first springs 40 aand 40 b to extend and impart a force F_(S1) piston 50, which causes thepiston 50 to start moving toward the nosepiece 28. This initial movementof the piston 50 reduces the likelihood that the heat generated by theelectrical current discharged from the capacitors will weld the piston50 to the first and second rails 35 a and 35 b. The charge switch 120 isopen.

As shown in FIG. 5 , closing the discharge switch 125 also causes thefirst and second capacitors 130 a and 130 b to discharge electricalcurrent I, which travels into the first rail 35 a. The electricalcurrent I travels across the conductive portion of the piston 50, intothe second rail 35 b, and exits the second rail 35 b toward thedischarge switch 125. This electrical current I induces a magnetic fieldB_(a) in the first rail 35 a, a magnetic field B_(p) in the piston 50,and a magnetic field B_(b) in the second rail 35 b. The combination ofthe electrical current I and the magnetic fields B_(a), B_(p), and B_(b)induce a Lorentz force F_(C) that acts on the piston 50 to move thepiston 50 toward the nosepiece 28.

FIG. 6 shows the rail nailer 10 after the first and second capacitors130 a and 130 b discharged and the discharge switch 125 has opened. Thepiston 50 has reached the firing position at the second ends of thefirst and second rails 35 a and 35 b, and the driver blade 55 hascontacted a fastener housed in the nosepiece 28 and driven the fastenerfrom the nosepiece 28 into a workpiece (not shown). The piston 50 hascompressed second springs 45 a and 45 b. In this example embodiment, thedischarge switch 125 is operably connected to the second springs 45 aand 45 b such that compression of the first and second springs 45 a and45 b to a particular extent—here, the extent at which the piston 50 isin the firing position—causes the discharge switch 125 to open. In otherembodiments, the rail nailer includes a suitable sensor, such as (butnot limited to) a mechanical sensor, an optical sensor, or a Hall effectsensor, operably connected to the discharge switch 125 and positioned totrip when the piston 50 reaches a particular position (such as thefiring position). In these embodiments, the discharge switch 125 opensresponsive to the sensor trip.

Additionally, since the battery management system has detected thatcharge of at least one of the first and second capacitors 130 a and 130b has fallen below the upper charge level threshold, the batterymanagement system closes the charge switch 120 to enable the battery 110to again charge the first and second capacitors 130 a and 130 b.

As shown in FIG. 7 , after the piston 50 stopped moving and reached thefiring position, the second springs 45 a and 45 b extended to impart aforce F_(S2) on the piston 50 to cause the piston 50 to move away fromthe nosepiece 28 and toward the pre-firing position. The charge switch120 remains closed and the battery 110 still charges the first andsecond capacitors 130 a and 130 b.

As shown in FIG. 8 , the force F_(S2) the second springs 45 a and 45 bimparted on the piston 50 caused the piston 50 to compress the firstsprings 40 a and 40 b and reach the pre-firing position. The lockingdevice of the piston movement and locking assembly locks the piston 50in place in the pre-firing position. The charge switch 120 remainsclosed and the battery 110 still charges the first and second capacitors130 a and 130 b.

In certain embodiments, the rail nailer 10 includes a suitable coolingsystem (not shown), such as a fan or a radiator, to dissipate heatgenerated responsive to capacitor discharge.

Various changes and modifications to the above-described embodimentsdescribed herein will be apparent to those skilled in the art. Thesechanges and modifications can be made without departing from the spiritand scope of this present subject matter and without diminishing itsintended advantages. It is therefore intended that such changes andmodifications be covered by the claims below.

The invention claimed is:
 1. A fastener-driving tool comprising: ahousing; a piston supported by the housing; a winding supported by thehousing, said winding associated with the piston and configured with thepiston such that when an electric current travels through the winding,the electric current induces a Lorentz force on the piston to causeactuation of the piston; a plurality of capacitors electricallyconnected to the winding such that electrical current discharged fromthe capacitors causes actuation of the piston; a discharge switchelectrically connected to the plurality of capacitors, the dischargeswitch configured to control when the electrical current is dischargedfrom the plurality of capacitors, and further configured to openresponsive to a position of the piston; a cooling system supported bythe housing, the cooling system including one of a fan and a radiator,the cooling system configured to dissipate heat generated from theelectrical current discharged from the plurality of capacitors; and apower source electrically connectable to the capacitors to charge thecapacitors.
 2. The fastener-driving tool of claim 1, wherein theplurality of capacitors have different capacities.
 3. Thefastener-driving tool of claim 1, wherein the plurality of capacitorsare supercapacitors.
 4. The fastener-driving tool of claim 1, whereinthe plurality of capacitors are of different sizes.
 5. Thefastener-driving tool of claim 1, which includes a charge switch,wherein the power source is electrically connected to the plurality ofcapacitors when the charge switch is closed and not electricallyconnected to the plurality of capacitors when the charge switch is open.6. The fastener-driving tool of claim 5, which includes a power sourcemanagement system operably connected to the charge switch and includinga sensor configured to detect charge levels of each of the plurality ofcapacitors.
 7. The fastener-driving tool of claim 6, wherein the powersource management system is configured to (a) monitor the charges levelsof the plurality of capacitors; (b) open the charge switch responsive tothe charge levels of the plurality of capacitors reaching a firstthreshold; and (c) afterwards, close the charge switch responsive to thecharge levels of the plurality of capacitors falling to a secondthreshold, wherein the second threshold is lower than the firstthreshold.
 8. The fastener-driving tool of claim 7, wherein closing thedischarge switch completes a discharge circuit and causes the electricalcurrent to discharge from the plurality of capacitors.
 9. Thefastener-driving tool of claim 8, wherein: (a) when the fastener-drivingtool is in a first operating mode, the discharge switch closesresponsive to a first actuation event followed by a second actuationevent; and (b) when the fastener-driving tool is in a different secondoperating mode, the discharge switch closes responsive to only thesecond actuation event.
 10. The fastener-driving tool of claim 1, whichincludes a battery management system configured to monitor charge levelsof the plurality of capacitors and automatically control whether a powersource is electrically connected to the plurality of capacitors based onthe charge level of the plurality of capacitors.
 11. Thefastener-driving tool of claim 10, wherein the battery management systemis configured to electrically connect the power source to the pluralityof capacitors responsive to the charge levels falling below a firstthreshold.
 12. The fastener-driving tool of claim 11, wherein thebattery management system is configured to electrically disconnect thepower source from the plurality of capacitors responsive to the chargelevels reaching a different second threshold.
 13. The fastener-drivingtool of claim 10, wherein the battery management system is configuredto: (a) while no actuations of the piston are occurring, charge theplurality of capacitors until each capacitor reaches its capacity; and(b) while an actuation of the piston is occurring, charge or not chargethe plurality of capacitors.
 14. A fastener-driving tool comprising: ahousing; a piston supported by the housing; a winding supported by thehousing, said winding associated with the piston and configured with thepiston such that when an electric current travels through the winding,the electric current induces a Lorentz force on the piston to causeactuation of the piston; at least one spring supported by the housingand compressible by the piston and configured to cause the return of thepiston after actuation of the piston; at least one capacitorelectrically connected to the winding such that electrical currentdischarged from the at least one capacitor causes actuation of thepiston; a discharge switch electrically connected to the at least onecapacitor, the discharge switch configured to control when theelectrical current is discharged from the at least one capacitor, andfurther configured to open responsive to a position of the piston; acooling system supported by the housing, the cooling system includingone of a fan and a radiator, the cooling system configured to dissipateheat generated from the electrical current discharged from the at leastone capacitor; and a power source electrically connectable to the atleast one capacitor to charge the at least one capacitor.
 15. Thefastener-driving tool of claim 14, wherein the at least one capacitor isa supercapacitor.
 16. The fastener-driving tool of claim 14, whereinclosing the discharge switch completes a discharge circuit and causesthe electrical current to discharge from the at least one capacitor. 17.The fastener-driving tool of claim 16, wherein the discharge switchopens responsive to compression of the at least one spring by thepiston.
 18. The fastener-driving tool of claim 16, wherein: (a) when thefastener-driving tool is in a first operating mode, the discharge switchcloses responsive to a first actuation event followed by a secondactuation event; and (b) when the fastener-driving tool is in a secondoperating mode, the discharge switch closes responsive to only thesecond actuation event.
 19. The fastener-driving tool of claim 14, whichincludes a plurality of springs supported by the housing, said pluralityof springs compressible by the piston and configured to assist in returnof the piston after actuation of the piston.
 20. The fastener-drivingtool of claim 19, wherein closing the discharge switch completes adischarge circuit and causes the electrical current to discharge fromthe at least one capacitor, wherein the discharge switch opensresponsive to compression of the plurality of springs by the piston. 21.The fastener-driving tool of claim 17, which includes a plurality ofcapacitors electrically connected to the winding so that electricalcurrent discharged from the plurality of capacitors causes actuation ofthe piston, wherein the plurality of capacitors have differentcapacities.